Refrigerator

ABSTRACT

The present disclosure relates to a refrigerator. The refrigerator according to an embodiment of the present disclosure comprises: an evaporator; a defrost heater; a temperature sensor to sense ambient temperature around the evaporator; and a controller to control the defrost heater, wherein the controller is configured to: perform a defrost operation mode in a case of reaching a defrosting operation start time point; perform, based on the defrost operation mode, a continuous operation mode in which the defrost heater is continuously turned on, and a pulse operation mode in which the defrost heater is repeatedly turned on and off; and perform the continuous operation mode again after performing the pulse operation mode. Accordingly, defrosting efficiency may be improved, and power consumption may be reduced.

BACKGROUND Field of the Disclosure

The present disclosure relates to a refrigerator, and more particularly,to a refrigerator capable of improving defrosting efficiency and powerconsumption.

Description of the Related Art

For long-term storage of foods in a refrigerator, a refrigeratortemperature is reduced using a compressor and an evaporator. Forexample, a freezer compartment in the refrigerator is maintained at atemperature of approximately −18° C.

Meanwhile, in order to improve refrigerator performance, it is desirableto remove frost which may be on the evaporator when the evaporatoroperates.

Korean Patent Application Laid-Open No. 10-2001-0026176 (hereinafter,referred to as Prior Document 1) relates to a method for controlling adefrost heater of a refrigerator, in which the defrost heater is turnedon when a certain time for defrosting arrives, and turned off after thelapse of a certain period of time.

However, according to Prior Document 1, since the ON time and the OFFtime of the defrost heater are based on a certain time or apredetermined time, defrosting is not performed according to the actualamount of frost of an evaporator. That is, when the amount of frost islarge, defrosting is not performed properly, or when the amount of frostis small, unnecessary defrosting is performed, thereby unnecessarilyconsuming power.

U.S. Pat. No. 6,694,754 (hereinafter, referred to as Prior Document 2)relates to a refrigerator having a pulse-based defrost heater,disclosing that the On and off time of a defrost heater is determinedbased on time.

According to Prior Document 2, since the ON time and the OFF time of thedefrost heater are determined based on time, defrosting is not performedaccording to the actual amount of frost of an evaporator. That is, whenthe amount of frost is large, defrosting is not performed properly, orwhen the amount of frost is small, unnecessary defrosting is performed,thereby unnecessarily consuming power.

Korean Patent Application Laid-Open No. 10-2016-0053502 (hereinafter,referred to as Prior Document 3) relates to a defrosting device, arefrigerator having the same, and a control method of the defrostingdevice, in which the On and off time of a defrost heater determinedbased on time or time and temperature.

According to Prior Document 3, since the ON time and the OFF time of thedefrost heater are determined based on time or time and temperature,defrosting is not performed according to the actual amount of frost ofan evaporator. That is, when the amount of frost is large, defrosting isnot performed properly, or when the amount of frost is small,unnecessary defrosting is performed, thereby unnecessarily consumingpower.

SUMMARY

An aspect of the present disclosure provides a refrigerator capable ofimproving defrosting efficiency and power consumption.

Another aspect of the present disclosure provides a refrigerator capableof performing a continuous operation mode again after a pulse operationmode of a defrost heater.

In an aspect, a refrigerator includes: an evaporator configured toperform heat exchange; a defrost heater configured to operate to removefrost formed on the evaporator; a temperature sensor configured todetect an ambient temperature of the evaporator; and a controllerconfigured to control the defrost heater, wherein, in response to adefrosting operation start time point arriving, the controller isconfigured to perform a defrost operation mode, perform a continuousoperation mode, in which the defrost heater is continuously turned on,and a pulse operation mode, in which the defrost heater is repeatedlyturned on and off based on the defrost operation mode, and is configuredto perform the continuous operation mode again after performing thepulse operation mode.

In response to a return condition to the continuous operation mode ofthe defrost heater arriving while performing the pulse operation mode,the controller may be configured to perform the continuous operationmode.

In response to a value related to the temperature detected by thetemperature sensor doing not reach a reference value while performingthe pulse operation mode, the controller may be configured to performthe continuous operation mode.

In response to the temperature detected by the temperature sensor beingbelow a reference temperature while performing the pulse operation mode,the controller may be configured to perform the continuous operationmode.

In response to a change rate of the temperature detected by thetemperature sensor being less than or equal to a change rate of thereference temperature while performing the pulse operation mode, thecontroller may be configured to perform the continuous operation mode.

In response to the temperature detected by the temperature sensor doingnot reach a target temperature within a certain time while performingthe pulse operation mode, the controller may be configured to performthe continuous operation mode.

In response to a sum of an ON time of the defrost heater whileperforming the pulse operation mode being greater than or equal to areference level, the controller may be configured to perform thecontinuous operation mode.

In response to a sum of the number of opening times the defrost heaterwhile performing the pulse operation mode being greater than or equal tothe reference number of opening times, the controller may be configuredto perform the continuous operation mode.

The sum of the ON time of the defrost heater while performing the pulseoperation mode is greater than a sum of a continuous ON time of thedefrost heater in the continuous operation mode, the controller may beconfigured to perform the continuous operation mode.

In response to a door open period being greater than or equal to anallowable period while performing the pulse operation mode, thecontroller may be configured to perform the continuous operation mode.

In response to humidity in the refrigerator being greater than or equalto reference humidity while performing the pulse operation mode, thecontroller may be configured to perform the continuous operation mode.

In response to a defrosting operation start time point arriving whileperforming a normal cooling operation mode, the controller may beconfigured to perform the defrost operation mode including a pre-defrostcooling mode, a heater operation mode, and a post-defrost cooling mode,and perform the continuous operation mode of the defrost heater, and thepulse operation mode, in which the defrost heater is repeatedly turnedon and off, based on the heater operation mode.

The controller may be configured to continuously turn on the defrostheater based on the continuous operation mode, in response to a changerate of the ambient temperature of the evaporator detected by thetemperature sensor being greater than or equal to a first referencevalue in an ON state of the defrost heater, enter the pulse operationmode and turn off the defrost heater, and in response to the change rateof the ambient temperature of the evaporator being less than or equal toa second reference value less than the first reference value in a statein which the defrost heater is turned off during the pulse operationmode, turn on the defrost heater.

The controller may be configured to continuously turn on the defrostheater based on the continuous operation mode, and repeatedly turn onand off the defrost heater for the change rate of the ambienttemperature of the evaporator to be between the first reference valueand the second reference value based on the pulse operation mode.

The controller may be configured to, as the number of opening times ofthe cooling compartment door increases, decrease a duration of thedefrost operation mode.

The controller may be configured to control a peak temperature arrivaltime point of the evaporator in response to the continuous operationmode and the pulse operation mode being performed to be later than thepeak temperature arrival time point of the evaporator in response to thedefrost heater being only continuously turned on in the defrostoperation mode.

The controller may be configured to control a size of a second sectionrelated to temperature versus time between a phase-change temperatureand the defrost end temperature in response to the continuous operationmode and the pulse operation mode being performed in the defrostoperation mode to be greater than a size of a first section related totemperature versus time between the phase-change temperature and thedefrost end temperatures only in response to the defrost heater beingcontinuously turned on in the defrost operation mode.

The controller may be configured to control an effective defrost inresponse to the continuous operation mode and the pulse operation modebeing performed in the defrost operation mode to be greater than theeffective defrost in response to the defrost heater being onlycontinuously turned on in the defrost operation mode.

The controller may be configured to control a heater OFF time point inresponse to the continuous operation mode and the pulse operation modebeing performed in the defrost operation mode to be later than theheater OFF time point in response to the defrost heater being onlycontinuously turned on in the defrost operation mode.

In response to a defrosting operation start time point arriving, thecontroller may be configured to perform the defrost operation modeincluding a pre-defrost cooling mode, a heater operation mode, and apost-defrost cooling mode, in response to the temperature detected bythe temperature sensor reaching the first temperature within a firstperiod during the continuous operation mode in which the defrost heateris continuously turned on based on the heater operation mode, performthe pulse operation mode in which the defrost heater is repeatedlyturned on and off, and in response to the period during which thetemperature detected by the temperature sensor reaching the firsttemperature while performing the continuous operation mode is greaterthan or equal to a second period greater than the first period,continuously perform the continuous operation mode.

In another aspect, a refrigerator includes: an evaporator configured toperform heat exchange; a defrost heater configured to operate to removefrost formed on the evaporator; a temperature sensor configured todetect an ambient temperature of the evaporator; and a controllerconfigured to control the defrost heater, wherein, in response to adefrosting operation start time point arriving, the controller isconfigured to perform a defrost operation mode, perform a continuousoperation mode, in which the defrost heater is continuously turned on,and a pulse operation mode, in which the defrost heater is repeatedlyturned on and off based on the defrost operation mode, and in responseto a return condition to the continuous operation mode of the defrostheater arriving while performing the pulse operation mode, perform thecontinuous operation mode again.

In further another aspect, a refrigerator includes: an evaporatorconfigured to perform heat exchange; a defrost heater configured tooperate to remove frost formed on the evaporator; a temperature sensorconfigured to detect an ambient temperature of the evaporator; and acontroller configured to control the defrost heater, wherein, inresponse to a defrosting operation start time point arriving, thecontroller is configured to perform the defrost operation mode includinga pre-defrost cooling mode, a heater operation mode, and a post-defrostcooling mode, in response to the temperature detected by the temperaturesensor reaching the first temperature within a first period during thecontinuous operation mode in which the defrost heater is continuouslyturned on based on the heater operation mode, perform the pulseoperation mode in which the defrost heater is repeatedly turned on andoff, and in response to the period during which the temperature detectedby the temperature sensor reaching the first temperature whileperforming the continuous operation mode is greater than or equal to asecond period greater than the first period, continuously perform thecontinuous operation mode.

In response to the temperature detected by the temperature sensorreaching a second temperature higher than the first temperature afterarriving at the first temperature between the first period and thesecond period while performing the continuous operation mode, thecontroller may be configured to perform the pulse operation mode afterthe defrost heater is turned off.

The controller may be configured to control an OFF period of the defrostheater before performing the pulse operation mode in response to thetemperature detected by the temperature sensor reaching a secondtemperature higher than the first temperature between the first periodand the second period to be greater than the OFF period of the defrostheater before performing the pulse operation mode in response to thetemperature detected by the temperature sensor reaching the firsttemperature within the first period.

In response to the temperature detected by the temperature sensorreaching the first temperature between the first period and the secondperiod while performing the continuous operation mode, the controllermay be configured to perform the pulse operation mode after the defrostheater is turned off.

The controller may be configured to control an OFF period of the defrostheater before performing the pulse operation mode in response to thetemperature detected by the temperature sensor reaching the firsttemperature between the first period and the second period to be greaterthan the OFF period of the defrost heater before performing the pulseoperation mode in response to the temperature detected by thetemperature sensor reaching the first temperature within the firstperiod.

The controller may be configured to, as the change rate of thetemperature detected by the temperature sensor decreases whileperforming the continuous operation mode, increase a delay of a starttime point of the pulse operation mode.

The controller may be configured to, as the change rate of thetemperature detected by the temperature sensor decreases whileperforming the continuous operation mode, increase the duration of thepulse operation mode.

Effects of the Disclosure

A refrigerator according to an embodiment of the present disclosureincludes: an evaporator configured to perform heat exchange; a defrostheater configured to operate to remove frost formed on the evaporator; atemperature sensor configured to detect an ambient temperature of theevaporator; and a controller configured to control the defrost heater,wherein, in response to a defrosting operation start time pointarriving, the controller is configured to perform a defrost operationmode, perform a continuous operation mode, in which the defrost heateris continuously turned on, and a pulse operation mode, in which thedefrost heater is repeatedly turned on and off based on the defrostoperation mode, and is configured to perform the continuous operationmode again after performing the pulse operation mode. Accordingly, thepresent disclosure can improve a defrosting efficiency and reduce powerconsumption. In particular, since the defrosting is performed accordingto the amount of frost of the actual evaporator, it is possible toimprove defrosting efficiency and power consumption.

In response to a return condition to the continuous operation mode ofthe defrost heater arriving while performing the pulse operation mode,the controller may be configured to perform the continuous operationmode. Accordingly, it is possible to improve the defrosting efficiencywhile stably performing the defrosting.

In response to a value related to the temperature detected by thetemperature sensor doing not reach a reference value while performingthe pulse operation mode, the controller may be configured to performthe continuous operation mode. Accordingly, it is possible to improvethe defrosting efficiency while stably performing the defrosting.

In response to the temperature detected by the temperature sensor beingbelow a reference temperature while performing the pulse operation mode,the controller may be configured to perform the continuous operationmode. Accordingly, it is possible to improve the defrosting efficiencywhile stably performing the defrosting.

In response to a change rate of the temperature detected by thetemperature sensor being less than or equal to a change rate of thereference temperature while performing the pulse operation mode, thecontroller may be configured to perform the continuous operation mode.Accordingly, it is possible to improve the defrosting efficiency whilestably performing the defrosting.

In response to the temperature detected by the temperature sensor doingnot reach a target temperature within a certain time while performingthe pulse operation mode, the controller may be configured to performthe continuous operation mode. Accordingly, it is possible to improvethe defrosting efficiency while stably performing the defrosting.

In response to a sum of an ON time of the defrost heater whileperforming the pulse operation mode being greater than or equal to areference level, the controller may be configured to perform thecontinuous operation mode. Accordingly, it is possible to improve thedefrosting efficiency while stably performing the defrosting.

In response to a sum of the number of opening times the defrost heaterwhile performing the pulse operation mode being greater than or equal tothe reference number of opening times, the controller may be configuredto perform the continuous operation mode. Accordingly, it is possible toimprove the defrosting efficiency while stably performing thedefrosting.

The sum of the ON time of the defrost heater while performing the pulseoperation mode is greater than a sum of a continuous ON time of thedefrost heater in the continuous operation mode, the controller may beconfigured to perform the continuous operation mode. Accordingly, it ispossible to improve the defrosting efficiency while stably performingthe defrosting.

In response to a door open period being greater than or equal to anallowable period while performing the pulse operation mode, thecontroller may be configured to perform the continuous operation mode.Accordingly, it is possible to improve the defrosting efficiency whilestably performing the defrosting.

In response to humidity in the refrigerator being greater than or equalto reference humidity while performing the pulse operation mode, thecontroller may be configured to perform the continuous operation mode.Accordingly, it is possible to improve the defrosting efficiency whilestably performing the defrosting.

Meanwhile, in response to a defrosting operation start time pointarriving while performing a normal cooling operation mode the controllermay be configured to perform the defrost operation mode including apre-defrost cooling mode, a heater operation mode, and a post-defrostcooling mode, and control the continuous operation mode of the defrostheater and the pulse operation mode, in which the defrost heater isrepeatedly turned on and off, to be performed based on the heateroperation mode. Accordingly, it is possible to improve the defrostingefficiency and reduce the power consumption.

Meanwhile, the controller may be configured to continuously turn on thedefrost heater based on the continuous operation mode, and enter thepulse operation mode and turn off the defrost heater in response to thechange rate of the ambient temperature of the evaporator detected by thetemperature sensor being greater than or equal to the first referencevalue in the ON state of the defrost heater, and turn on the defrostheater in response to the change rate of the ambient temperature of theevaporator being less than or equal to the second reference value lessthan the first reference value in the state in which the defrost heateris turned off during the pulse operation mode. Accordingly, it ispossible to improve the defrosting efficiency and reduce the powerconsumption.

Meanwhile, the controller may be configured to turn off the defrostheater based on the heater pulse operation end condition. Accordingly,it is possible to improve the defrosting efficiency and reduce the powerconsumption.

Meanwhile, the controller may be configured to continuously turn on thedefrost heater based on the continuous operation mode, and repeatedlyturn on and off the defrost heater for the change rate of thetemperature around the evaporator being between the first referencevalue and the second reference value based on the pulse operation mode.Accordingly, it is possible to improve the defrosting efficiency andreduce the power consumption.

Meanwhile, in response to the temperature detected by the temperaturesensor being a predetermined temperature, the controller may beconfigured to perform the pulse operation mode. Accordingly, the presentdisclosure can improve a defrosting efficiency and reduce powerconsumption.

Meanwhile, in response to the temperature detected by the temperaturesensor being a predetermined temperature, and an execution period of thecontinuous operation mode being longer than a predetermined period, thecontroller may be configured to perform the pulse operation mode.Accordingly, it is possible to improve the defrosting efficiency andreduce the power consumption.

Meanwhile, when the execution period of the continuous operation mode islonger than a predetermined period, the controller may be configured toperform the pulse operation mode. Accordingly, it is possible to improvethe defrosting efficiency and reduce the power consumption.

Meanwhile, the controller may be configured to perform the pulseoperation mode based on the temperature change rate of the temperaturedetected by the temperature sensor. Accordingly, it is possible toimprove the defrosting efficiency and reduce the power consumption.

Meanwhile, the controller may be configured to operate the heater withpower inversely proportional to the temperature change rate of thetemperature detected by the sensor during the pulse operation mode.Accordingly, it is possible to improve the defrosting efficiency andreduce the power consumption.

Meanwhile, the controller may be configured to, as the number of openingtimes of the cooling compartment door increases, decrease the durationof the defrost operation mode. Accordingly, it is possible to improvethe defrosting efficiency and reduce the power consumption.

Meanwhile, the controller may be configured to control a peaktemperature arrival point of the evaporator in response to thecontinuous operation mode and the pulse operation mode being performedin the defrost operation mode to be later than a peak temperaturearrival point of the evaporator in response to the defrost heater beingonly continuously turned on in the defrost operation mode. Accordingly,defrosting efficiency may be improved and power consumption may beimproved.

Meanwhile, the controller may be configured to control a size of asecond section related to a temperature versus time between aphase-change temperature and a defrost end temperature in response tothe continuous operation mode and the pulse operation mode beingperformed in the defrost operation mode to be greater than a size of afirst section related to a temperature versus time between thephase-change temperature and the defrost end temperature in response tothe defrost heater being only continuously turned on in the defrostoperation mode. Accordingly, defrosting efficiency may be improved andpower consumption may be improved.

Meanwhile, the controller may be configured to control an effectivedefrost in response to the continuous operation mode and the pulseoperation mode being performed in the defrost operation mode to begreater than an effective defrost in response to the defrost heaterbeing only continuously turned on in the defrost operation mode.Accordingly, defrosting efficiency may be improved and power consumptionmay be improved.

Meanwhile, the controller may be configured to control a heater OFF timepoint in response to the continuous operation mode and the pulseoperation mode being performed in the defrost operation mode to be laterthan a heater OFF time point in response to the defrost heater beingonly continuously turned on in the defrost operation mode. Accordingly,defrosting efficiency may be improved and power consumption may beimproved.

Meanwhile, in response to a defrosting operation start time pointarriving, the controller may be configured to perform the defrostoperation mode including a pre-defrost cooling mode, a heater operationmode, and a post-defrost cooling mode, in response to the temperaturedetected by the temperature sensor reaching the first temperature withina first period during the continuous operation mode in which the defrostheater is continuously turned on based on the heater operation mode,perform the pulse operation mode in which the defrost heater isrepeatedly turned on and off, and in response to the period during whichthe temperature detected by the temperature sensor reaching the firsttemperature while performing the continuous operation mode is greaterthan or equal to a second period greater than the first period,continuously perform the continuous operation mode. Accordingly, it ispossible to improve the defrosting efficiency and reduce the powerconsumption.

A refrigerator according to another embodiment of the present disclosureincludes: an evaporator configured to perform heat exchange; a defrostheater configured to operate to remove frost formed on the evaporator; atemperature sensor configured to detect an ambient temperature of theevaporator; and a controller configured to control the defrost heater,wherein, in response to a defrosting operation start time pointarriving, the controller is configured to perform a defrost operationmode, perform a continuous operation mode, in which the defrost heateris continuously turned on, and a pulse operation mode, in which thedefrost heater is repeatedly turned on and off based on the defrostoperation mode, and in response to a return condition to the continuousoperation mode of the defrost heater arriving while performing the pulseoperation mode, perform the continuous operation mode again.Accordingly, it is possible to improve the defrosting efficiency andreduce the power consumption. In particular, since the defrosting isperformed according to the amount of frost of the actual evaporator, itis possible to improve defrosting efficiency and power consumption.

A refrigerator according to another embodiment of the present disclosureincludes: an evaporator configured to perform heat exchange; a defrostheater configured to operate to remove frost formed on the evaporator; atemperature sensor configured to detect an ambient temperature of theevaporator; and a controller configured to control the defrost heater,wherein, in response to a defrosting operation start time pointarriving, the controller is configured to perform the defrost operationmode including a pre-defrost cooling mode, a heater operation mode, anda post-defrost cooling mode, in response to the temperature detected bythe temperature sensor reaching the first temperature within a firstperiod during the continuous operation mode in which the defrost heateris continuously turned on based on the heater operation mode, performthe pulse operation mode in which the defrost heater is repeatedlyturned on and off, and in response to the period during which thetemperature detected by the temperature sensor reaching the firsttemperature while performing the continuous operation mode is greaterthan or equal to a second period greater than the first period,continuously perform the continuous operation mode.

Accordingly, it is possible to improve the defrosting efficiency andreduce the power consumption. In particular, since the defrosting isperformed according to the amount of frost of the actual evaporator, itis possible to improve defrosting efficiency and power consumption.

Meanwhile, in response to the temperature detected by the temperaturesensor reaching a second temperature higher than the first temperatureafter arriving at the first temperature between the first period and thesecond period while performing the continuous operation mode, thecontroller may be configured to perform the pulse operation mode afterthe defrost heater is turned off. Accordingly, it is possible to improvethe defrosting efficiency and reduce the power consumption.

Meanwhile, the controller may be configured to control an OFF period ofthe defrost heater before performing the pulse operation mode inresponse to the temperature detected by the temperature sensor reachinga second temperature higher than the first temperature between the firstperiod and the second period to be greater than the OFF period of thedefrost heater before performing the pulse operation mode in response tothe temperature detected by the temperature sensor reaching the firsttemperature within the first period. Accordingly, it is possible toimprove the defrosting efficiency and reduce the power consumption.

Meanwhile, in response to the temperature detected by the temperaturesensor reaching the first temperature between the first period and thesecond period while performing the continuous operation mode, thecontroller may be configured to perform the pulse operation mode afterthe defrost heater is turned off. Accordingly, it is possible to improvethe defrosting efficiency and reduce the power consumption.

The controller may be configured to control an OFF period of the defrostheater before performing the pulse operation mode in response to thetemperature detected by the temperature sensor reaching the firsttemperature between the first period and the second period to be greaterthan the OFF period of the defrost heater before performing the pulseoperation mode in response to the temperature detected by thetemperature sensor reaching the first temperature within the firstperiod. Accordingly, it is possible to improve the defrosting efficiencyand reduce the power consumption.

Meanwhile, the controller may be configured to, as the change rate ofthe temperature detected by the temperature sensor decreases whileperforming the continuous operation mode, increase a delay of a starttime point of the pulse operation mode. Accordingly, it is possible toimprove the defrosting efficiency and reduce the power consumption.

Meanwhile, the controller may be configured to, as the change rate ofthe temperature detected by the temperature sensor decreases whileperforming the continuous operation mode, increase the duration of thepulse operation mode. Accordingly, it is possible to improve thedefrosting efficiency and reduce the power consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a refrigerator according to anembodiment of the present disclosure;

FIG. 2 is a perspective view of a door of the refrigerator of FIG. 1 ;

FIG. 3 is a view schematically illustrating a configuration of therefrigerator of FIG. 1 ;

FIG. 4 is a block diagram schematically illustrating the inside of therefrigerator shown in FIG. 1 ;

FIG. 5A is a perspective view illustrating an example of an evaporatorassociated with the present disclosure;

FIG. 5B is a diagram referenced in the description of FIG. 5A;

FIG. 6 is a flowchart illustrating a method of operating a refrigeratoraccording to an embodiment of the present disclosure;

FIGS. 7A to 13 are diagrams referenced in the description of FIG. 6 ;

FIG. 14 is a flowchart illustrating a method of operating a defrostheater according to another embodiment of the present disclosure;

FIGS. 15A to 15D are diagrams referenced in the description of FIG. 14 ;

FIG. 16 is a flowchart illustrating a defrosting method according toanother embodiment of the present disclosure; and

FIGS. 17A to 17D are diagrams referenced in the description of FIG. 16 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present disclosure will be described in further detailwith reference to the accompanying drawings.

The suffixes “module” and “unit” in elements used in description beloware given only in consideration of ease in preparation of thespecification and do not have specific meanings or functions. Therefore,the suffixes “module” and “unit” may be used interchangeably.

FIG. 1 is a perspective view illustrating a refrigerator according to anembodiment of the present disclosure.

Referring to the drawings, a refrigerator 100 according to an embodimentof the present disclosure forms a rough outer shape by a case 110 havingan internal space divided, although not shown, into a freezercompartment and a refrigerating compartment, a freezer compartment door120 that shields the freezer compartment, and a refrigerator door 140 toshield the refrigerating compartment.

In addition, the front surface of the freezer compartment door 120 andthe refrigerating compartment door 140 is further provided with a doorhandle 121 protruding forward, so that a user easily grips and rotatesthe freezer compartment door 120 and the refrigerating compartment door140.

Meanwhile, the front surface of the refrigerating compartment door 140may be further provided with a home bar 180 which is a convenient meansfor allowing a user to take out a storage such as a beverage containedtherein without opening the refrigerating compartment door 140.

In addition, the front surface of the freezer compartment door 120 maybe provided with a dispenser 160 which is a convenient means forallowing the user to easily take out ice or drinking water withoutopening the freezer compartment door 120, and a control panel 210 forcontrolling the driving operation of the refrigerator 100 and displayingthe state of the refrigerator 100 being operated on a screen may befurther provided in an upper side of the dispenser 160.

Meanwhile, in the drawing, it is illustrated that the dispenser 160 isdisposed in the front surface of the freezer compartment door 120, butis not limited thereto, and may be disposed in the front surface of therefrigerating compartment door 140.

The control panel 210 may include an input device 220 formed of aplurality of buttons, and a display device 230 for displaying a controlscreen, an operation state, and the like.

The display device 230 displays information such as a control screen, anoperation state, a temperature inside the refrigerator, and the like.For example, the display device 230 may display the set temperature ofthe freezer compartment and the set temperature of the refrigeratingcompartment.

The display device 230 may be implemented in various ways, such as aliquid crystal display (LCD), a light emitting diode (LED), an organiclight emitting diode (OLED), and the like. In addition, the displaydevice 230 may be implemented as a touch screen capable of serving asthe input device 220.

The input device 220 may include a plurality of operation buttons. Forexample, the input device 220 may include a freezer compartmenttemperature setting button (not shown) for setting the freezercompartment temperature, and a refrigerating compartment temperaturesetting button (not shown) for setting the refrigerating compartmenttemperature. Meanwhile, the input device 220 may be implemented as atouch screen that may also function as the display device 230.

Meanwhile, the refrigerator according to an embodiment of the presentdisclosure is not limited to a double door type shown in the drawing,but may be a one door type, a sliding door type, a curtain door type,and the like regardless of its type.

FIG. 2 is a perspective view of a door of the refrigerator of FIG. 1 .

Referring to the drawing, a freezer compartment 155 is disposed insidethe freezer compartment door 120, and a refrigerating compartment 157 isdisposed inside the refrigerating compartment door 140.

FIG. 3 is a view schematically illustrating a configuration of therefrigerator of FIG. 1 .

Referring to the drawing, the refrigerator 100 may include a compressor112, a condenser 116 for condensing a refrigerant compressed by thecompressor 112, a freezer compartment evaporator 122 which is suppliedwith the refrigerant condensed in the condenser 116 to evaporate, and isdisposed in a freezer compartment (not shown), and a freezer compartmentexpansion valve 132 for expanding the refrigerant supplied to thefreezer compartment evaporator 122.

Meanwhile, in the drawing, it illustrated that a single evaporator isused, but it is also possible to use respective evaporators may be usedin the refrigerating compartment and the freezer compartment.

That is, the refrigerator 100 may further include a refrigeratingcompartment evaporator (not shown) disposed in a refrigeratingcompartment (not shown), a three-way valve (not shown) for supplying therefrigerant condensed in the condenser 116 to the refrigeratingcompartment evaporator (not shown) or the freezer compartment evaporator122, and a refrigerating compartment expansion valve (not shown) forexpanding the refrigerant supplied to the refrigerating compartmentevaporator (not shown).

In addition, the refrigerator 100 may further include a gas-liquidseparator (not shown) which separates the refrigerant passed through theevaporator 122 into a liquid and a gas.

In addition, the refrigerator 100 may further include a refrigeratingcompartment fan (not shown) and a freezer compartment fan 144 that suckcold air that passed through the freezer compartment evaporator 122 andblow the sucked cold air into a refrigerating compartment (not shown)and a freezer compartment (not shown) respectively.

In addition, the refrigerator 100 may further include a compressordriver 113 for driving the compressor 112, and a refrigeratingcompartment fan driver (not shown) and a freezer compartment fan driver145 for driving the refrigerating compartment fan (not shown) and thefreezer compartment 144.

Meanwhile, based on the drawing, since a common evaporator 122 is usedfor the refrigerating compartment and the freezer compartment, in thiscase, a damper (not shown) may be installed between the refrigeratingcompartment and the freezer compartment, and a fan (not shown) mayforcibly blow the cold air generated in one evaporator to be supplied tothe freezer compartment and the refrigerating compartment.

FIG. 4 is a block diagram schematically illustrating the inside of therefrigerator shown in FIG. 1 .

Referring to the drawings, the refrigerator of FIG. 4 includes acompressor 112, a machine room fan 115, the freezer compartment fan 144,a controller 310, a heater 330, a temperature sensor 320, and a memory240, and an evaporator 122.

In addition, the refrigerator may further include a compressor driver113, a machine room fan driver 117, a freezer compartment fan driver145, a heater driver 332, a display device 230, and an input device 220.

The compressor 112, the machine room fan 115, and the freezercompartment fan 144 are described with reference to The input device 220includes a plurality of operation buttons, and transmits a signal for aninput freezer compartment set temperature or refrigerating compartmentset temperature to the controller 310.

The display device 230 may display an operation state of therefrigerator. Meanwhile, the display device 230 is operable under thecontrol of a display controller (not shown).

The memory 240 may store data necessary for operating the refrigerator.

For example, the memory 240 may store power consumption information foreach of the plurality of power consumption devices. In addition, thememory 240 may output corresponding power consumption information to thecontroller 310 based on the operation of each power consumption devicein the refrigerator.

The temperature sensor 320 detects a temperature in the refrigerator andtransmits a signal for the detected temperature to the controller 310.Here, the temperature sensor 320 detects the refrigerating compartmenttemperature and the freezer compartment temperature respectively. Inaddition, the temperature of each chamber in the refrigeratingcompartment or each chamber in the freezer compartment may be detected.

In order to control an ON/OFF operation of the compressor 112, the fan115 or 144, and the heater 330, as shown in the drawing, the controllermay control the compressor driver 113, the fan driver 117 or 145, theheater driver 332 to eventually control the compressor 112, the fan 115or 144, and the heater 330. Here, the fan driver may be the machine roomfan driver 117 or the freezer compartment fan driver 145.

For example, the controller 310 may output a corresponding speed commandvalue signal to the compressor driver 113 or the fan driver 117 or 145respectively.

The compressor driver 113 and the freezer compartment fan driver 145described above are provided with a compressor motor (not shown) and afreezer compartment fan motor (not shown) respectively, and each motor(not shown) may be operated at a target rotational speed under thecontrol of the controller 310.

Meanwhile, the machine room fan driver 117 includes a machine room fanmotor (not shown), and the machine room fan motor (not shown) may beoperated at a target rotational speed under the control of thecontroller 310.

When such a motor is a three-phase motor, it may be controlled by aswitching operation in an inverter (not shown) or may be controlled at aconstant speed by using an AC power source intactly. Here, each motor(not shown) may be any one of an induction motor, a Blush less DC (BLDC)motor, a synchronous reluctance motor (synRM) motor, and the like.

Meanwhile, as described above, the controller 310 may control theoverall operation of the refrigerator 100, in addition to the operationcontrol of the compressor 112 and the fan 115 or 144.

For example, as described above, the controller 310 may control theoverall operation of the refrigerant cycle based on the set temperaturefrom the input device 220. For example, the controller 310 may furthercontrol a three-way valve (not shown), a refrigerating compartmentexpansion valve (not shown), and a freezer compartment expansion valve132, in addition to the compressor driver 113, the refrigeratingcompartment fan driver 143, and the freezer compartment fan driver 145.In addition, the operation of the condenser 116 may also be controlled.In addition, the controller 310 may control the operation of the displaydevice 230.

Meanwhile, the cold air heat-exchanged in the evaporator 122 may besupplied to the freezer compartment or the refrigerating compartment bya fan or a damper (not shown).

Meanwhile, the heater 330 may be a freezer compartment defrost heater.For example, when only one freezer compartment evaporator 122 is used inthe refrigerator 100, the freezer compartment defrost heater 330 mayoperate to remove frost attached to the freezer compartment evaporator122. To this end, the heater driver 332 may control the operation of theheater 330. Meanwhile, the controller 310 may control the heater driver332.

Meanwhile, the heater 330 may include a freezer compartment defrostheater and a refrigerating compartment defrost heater. For example, whenthe freezer compartment evaporator 122 and the refrigerating compartmentevaporator (not shown) are separately used in the refrigerator 100, thefreezer compartment defrost heater 330 may operates to remove frostattached to the freezer compartment evaporator 122, and therefrigerating compartment defrost heater (not shown) may operate toremove frost attached to the refrigerating compartment evaporator. Tothis end, the heater driver 332 may control the operations of thefreezer compartment defrost heater 330 and the refrigerating compartmentdefrost heater.

FIG. 5A is a perspective view illustrating an example of an evaporatorrelated to the present disclosure, and FIG. 5B is a diagram referencedin the description of FIG. 5A.

First, referring to FIG. 5A, the evaporator 122 in the refrigerator 100may be a freezer compartment evaporator as described above withreference to FIG. 2 .

A sensor mounter 400 including a temperature sensor 320 may be attachedto the evaporator 122 in the refrigerator 100.

In the drawing, it is illustrated that a sensor mounter 400 is attachedto an upper cooling pipe of the evaporator 122 in the refrigerator 100.

The evaporator 122 includes a cooling pipe 131 extending from one sideof the accumulator 134 and a support 133 supporting the cooling pipe131.

The cooling pipe 131 may be repeatedly bent in a zigzag manner to formmultiple rows and may be filled with a refrigerant.

Meanwhile, the defrost heater 330 for defrosting may be disposed in thevicinity of the cooling pipe 131 of the evaporator 122.

In the drawing, it is illustrated that the defrost heater 330 isdisposed in the vicinity of the cooling pipe 131 in a lower region ofthe evaporator 122.

For example, since frost ICE is formed from a lower region of theevaporator 122 and grows in an upward direction, and thus, preferably,the defrost heater 330 may be disposed in the vicinity of the coolingpipe 131 in the lower region of the evaporator 122.

Accordingly, as shown in the drawing, the defrost heater 330 may bedisposed in a shape surrounding the cooling pipe 131 of the lower regionof the evaporator 122.

Meanwhile, FIG. 5B illustrates frost ICE is attached to the evaporator122.

In the drawing, it is illustrated that frost ICE is attached to acentral portion and a lower portion of the evaporator 122.

In particular, in the drawing, it is illustrated that frost ICE isformed on the defrost heater 330 to cover the defrost heater 330.

Meanwhile, when the defrost heater 330 operates, frost ICE is removedfrom the lower region of the evaporator 122 and may be gradually removedin the direction of the central region.

Meanwhile, in the present disclosure, a method for improving defrostingefficiency and power consumption when removing frost ICE, that is,defrosting, is proposed. This will be described with reference to FIG. 6and the following drawings.

FIG. 6 is a flowchart illustrating a method of operating a refrigeratoraccording to an embodiment of the present disclosure.

Referring to the drawings, the controller 310 of the refrigerator 100according to an embodiment of the present disclosure determines whethera defrosting operation start time point for defrosting arrives (S610).

For example, the controller 310 of the refrigerator 100 may determinewhether a defrosting operation start time point arrives while performinga normal cooling operation mode Pga.

The defrosting operation start time point may vary according to adefrost cycle.

For example, when the number of opening times a door of the coolingcompartment (the refrigerating compartment or the freezer compartment)increases, the amount of cold air supplied in the normal coolingoperation mode increases, and accordingly, a rate at which frost isformed on the evaporator 122 may increase.

Accordingly, when the number of opening times the door of the coolingcompartment (the refrigerating compartment or the freezer compartment)increases, the controller 310 of the refrigerator 100 may control suchthat a defrost cycle is shortened.

That is, when the number of opening times the door of the coolingcompartment (the refrigerating compartment or the freezer compartment)increases, the controller 310 of the refrigerator 100 may control thedefrosting operation start time point to be shortened.

Meanwhile, when a defrosting operation start condition is satisfied, forexample, in response to a defrosting operation start time pointarriving, the controller 310 of the refrigerator 100 may end the normalcooling operation mode, control to perform a defrost operation mode Pdf,and control the defrost heater 330 to be continuously turned on based ona heater operation mode PddT in the defrost operation mode Pdf (S615).

Next, the controller 310 of the refrigerator 100 may be configured toperform a pulse operation mode in which the defrost heater 330 isrepeatedly turned on and off by a heater pulse after the defrost heater330 is continuously turned on (S620).

For example, when the defrosting operation start condition is satisfied,the controller 310 of the refrigerator 100 may be configured to performthe defrost operation mode Pdf including a pre-defrost cooling mode Pbd,a heater operation mode PddT, and a post-defrost cooling mode pbf.

Also, based on the heater operation mode PddT, based on the defrostoperation mode pdf, the controller may be configured to perform acontinuous operation mode Pona in which the defrost heater 330 iscontinuously turned on and a pulse operation mode Ponb in which thedefrost heater 330 is repeatedly turned on and off.

Meanwhile, the controller 310 controls the defrost heater 330 to becontinuously turned on based on the continuous operation mode Pona, andin the ON state of the defrost heater 330, when a change rate of anambient temperature of the evaporator 122 detected by the temperaturesensor 320 is equal to or greater than a first reference value ref1, thecontroller 310 may enter the pulse operation mode Ponb to control thedefrost heater 330 to be turned off. Accordingly, defrosting efficiencyand power consumption may be improved.

Meanwhile, the controller 310 of the refrigerator 100 may control thedefrost heater 330 to be turned on and off based on a change rate of thetemperature detected by the temperature sensor 320 when the pulseoperation mode Ponb is performed.

For example, in response to performing the pulse operation mode Ponb, ifthe change rate of the temperature detected by the temperature sensor320 is equal to or greater than the first reference value ref1, thecontroller 310 of the refrigerator 100 may control the defrost heater330 to be turned off, and if the change rate of the temperature detectedby the temperature sensor 320 is less than or equal to a secondreference value ref2 less than the first reference value ref1, thecontroller 310 may control the defrost heater 330 to be turned on.Accordingly, since defrosting may be performed based on a change rate ΔTof the temperature, defrosting efficiency and power consumption may beimproved.

Next, the controller 310 of the refrigerator 100 determines whether apulse operation mode end time point arrives (S630), and if pulseoperation mode end time point arrives, the controller 310 turns off thedefrost heater 330 (S640).

For example, the pulse operation mode end time point may be a time pointat which the temperature detected by the temperature sensor 320 fallsbelow a phase-change temperature Trf1.

As another example, the pulse operation mode end time point may be anend time point of the defrosting operation or an end time point of theheater operation mode.

As such, the continuous operation mode Pona in which the defrost heater330 is continuously turned on and the pulse operation mode in which thedefrost heater 330 is repeatedly turned on and off are controlled to beperformed based on the change rate of the temperature detected by thetemperature sensor 320, defrosting efficiency and power consumption maybe improved by performing defrosting based on the change rate ΔT of thetemperature.

In particular, since defrosting is performed according to the actualamount of frost of the evaporator 122, defrosting efficiency and powerconsumption may be improved.

FIGS. 7A to 13 are diagrams referenced in the description of FIG. 6 .

First, FIG. 7A is a diagram illustrating a defrost heater HT and aswitching element RL for driving a defrost heater when one evaporatorand one defrost heater are used in the refrigerator 100.

Referring to the drawing, when only one freezer compartment evaporator122 is used in the refrigerator 100, the freezer compartment defrostheater HT may operate to remove frost attached to the freezercompartment evaporator 122.

To this end, the switching element RL in the heater driver 332 maycontrol the operation of the defrost heater HT. In this case, theswitching element RL may be a relay element.

That is, when the switching element RL is continuously turned on, thecontinuous operation mode Pona in which the defrost heater HT iscontinuously turned on may be performed, and when the switching elementRL is switched On and off, the pulse operation mode Ponb in which thedefrost heater HT is repeatedly turned on and off may be performed.

Next, FIG. 7B is a diagram illustrating defrost heaters HTa and HTb andswitching elements RLa and Rlb for driving the defrost heaters when twoevaporators and two defrost heaters are used in the refrigerator 100.

When a first defrost heater HTa is a freezer compartment defrost heater,a first switching element RLa in the heater driver 332 may control theoperation of the first defrost heater HTa. In this case, the firstswitching element RLa may be a relay element.

That is, when the first switching element RLa is continuously turned on,the continuous operation mode Pona in which the first defrost heater HTais continuously turned on may be performed, and when the first switchingelement RLa performs On and off switching, the pulse operation mode Ponbin which the first defrost heater HTa is repeatedly turned on and offmay be performed.

When a second defrost heater HTb is a refrigerating compartment defrostheater, a second switching element RLb in the heater driver 332 maycontrol the operation of the second defrost heater HTb. In this case,the second switching element RLb may be a relay element.

That is, when the second switching element RLb is continuously turnedon, the continuous operation mode Ponb in which the second defrostheater HTb is continuously turned on may be performed, and when thesecond switching element RLb performs On and off switching, the pulseoperation mode Ponb in which the second defrost heater HTb is repeatedlyturned on and off may be performed.

Meanwhile, On and off timings of the first switching element RLa and thesecond switching element RLb may be different from each other.Accordingly, it is possible to perform the defrosting of the freezercompartment evaporator and the defrosting of the refrigeratingcompartment evaporator, separately.

FIG. 8A is a diagram illustrating an example of a pulse waveformindicating an operation of one defrost heater of FIG. 7A.

Referring to the drawings, the horizontal axis of the pulse waveform Pshmay represent time and the vertical axis may represent a level.

When the defrosting cloud base start time To arrives, while performingthe normal cooling operation mode Pga, the controller 310 of therefrigerator 100 may end the normal cooling operation mode Pga andcontrol to perform the defrost operation mode pdf.

The defrost operation mode pdf may include a pre-defrost cooling modePbd between Toa and Ta, a heater operation mode PddT between Ta and Td,and a post-defrost cooling mode pbf between Td and Te.

Meanwhile, after the defrost operation mode pdf is ended, the normalcooling operation mode Pgb is performed again.

The defrost heater 330 is turned off in the normal cooling operationmode Pga and the normal cooling operation mode Pgb.

Meanwhile, the defrost heater 330 may be turned off in the pre-defrostcooling mode Pbd and the post-defrost cooling mode pbf of the defrostoperation mode Pdf.

Meanwhile, the defrost heater 330 may be continuously turned on in thecontinuous operation mode Pona of the heater operation mode PddT, andmay be repeatedly turned on and off in the pulse operation mode Ponb ofthe heater operation mode PddT.

The continuous operation mode Pona may be performed between Ta and Tb,and the pulse operation mode Ponb may be performed between Tb and Tc.

When only the continuous operation mode is performed and the defrostheater 330 is continuously turned on, if the amount of frost is large,defrosting may not be performed properly or if the amount of frost issmall, unnecessary defrosting may be performed, and thus, unnecessarypower consumption may be consumed.

Accordingly, in the present disclosure, the continuous operation modePona and the pulse operation mode Ponb are used in combination.Accordingly, defrosting efficiency and power consumption may beimproved.

FIG. 8B is a diagram illustrating an example of a pulse waveformindicating an operation of two defrost heaters of FIG. 7B.

Referring to the drawing, (a) of FIG. 8B shows a pulse waveform Pshaindicating an operation of the freezer compartment defrost heater, and(b) of FIG. 8B shows a pulse waveform Pshb indicating an operation ofthe refrigerating compartment defrost heater.

The pulse waveform Psha of (a) of FIG. 8B may be the same as the pulsewaveform Psh of FIG. 8A.

Meanwhile, since less frost may occur in the refrigerating compartmentevaporator than in the freezer compartment evaporator, an operatingsection of the refrigerating compartment defrost heater may be less thanan operating section of the freezer compartment defrost heater.

Referring to the pulse waveform Pshb of (b) of FIG. 8B, a period ofcontinuously turning on in the continuous operation mode Pona in theheater operation mode PddT may be less than a period of the pulsewaveform Psha of (a) of FIG. 8B.

In addition, referring to the pulse waveform Pshb of (b) of FIG. 8B, anON/OFF repetition period of the pulse operation mode Ponb in the heateroperation mode PddT may be less than the pulse waveform Psha of (a) ofFIG. 8B.

FIG. 9 is a diagram illustrating an example of cooling power supply anda defrost heater operation in the defrost operation mode Pdf of FIG. 8A.

Referring to the drawing, the defrost operation mode pdf may include apre-defrost cooling mode Pbd between To and Ta, a heater operation modePddT between Ta and Td, and a post-defrost cooling mode pbf between Tdand Te.

During a period To to T1 of the pre-defrost cooling mode Pbd, a level ofsupplied cooling power may be an R level, and during a period T1 to T2,a level of cooling power may be an F level greater than the R level.

Also, during a period T2 to T3 of the pre-defrost cooling mode Pbd, thecooling power supply may be stopped.

In addition, during a period T3 to Ta in the pre-defrost cooling modePbd, a level of supplied cooling power may be the R level.

According to the pre-defrost cooling mode Pbd, cooling power supply forcompensating for the stoppage of cooling power supply during the heateroperation mode PddT is performed.

Meanwhile, the cooling power supply may be performed by a compressor, athermoelectric element, or the like, and in the drawings, it isillustrated that the cooling power supply is performed by an operationof the compressor.

During a period To to T2 and T3 to Ta in which cooling power issupplied, the compressor operates, and during a period T2 to T3 in whichcooling power is not supplied, the compressor is turned off.

Meanwhile, during a period To to T1 in which the R level cooling poweris supplied, the refrigerating compartment fan may operate and thefreezer compartment fan may be turned off.

Meanwhile, during a period from a time point T1, at which the F levelcooling power is supplied, to a time point Ta, at which the pre-defrostcooling mode Pbd is ended, the refrigerating compartment fan may beturned off and the freezer compartment fan may be operated.

Meanwhile, during the period T2 to Ta, the defrost heater 330 should bemaintained in an OFF state.

Next, the defrost heater 330 may operate during the period of Ta to Tcin the period of Ta to Td of the heater operation mode PddT.

As shown in FIG. 8A, the continuous operation mode Pona may be performedduring the period of Ta and Tb of the heater operation mode PddT period,and the heater operation mode PddT may be performed during the Tb and Tcperiods.

Meanwhile, the defrost heater 330 may be turned off from Tc, which is anend time point of the continuous operation mode Pona, to Td.

Meanwhile, during the period of the heater operation mode PddT, thecompressor and the refrigerating compartment fan may be turned off.

Meanwhile, during the period of the heater operation mode PddT, thefreezer compartment fan may be turned off. In particular, it ispreferable that the freezer compartment fan is turned off from Tc, whichis the end time point of the continuous operation mode Pona, to Td.

After the heater operation mode PddT, the post-defrost cooling mode Pbfis performed.

During the period of Td to T4 in the post-defrost cooling mode Pbf, alevel of the supplied cooling power may be an R+F level, and the largestlevel of cooling power may be supplied.

In addition, during the period of T4 to T6 in the post-defrost coolingmode Pbf, a level of the supplied cooling power may be F level, and thecooling power supply may be stopped during the period T6 to Te.

According to the post-defrost cooling mode Pbf, the largest level ofcooling power supply may be performed according to the stopping of thecooling power supply during the heater operation mode PddT.

During the period of Td to T6 in which cooling power is supplied, thecompressor operates, and the compressor is turned off during the periodof T6 to Te in which cooling power is not supplied.

Meanwhile, during the period of Td to T4 in which the R+F level ofcooling power is supplied, the refrigerating compartment fan and thefreezer compartment fan may be turned off together.

Meanwhile, during the period of T4 to T6 in which the F level coolingpower is supplied, the refrigerating compartment fan may be turned offand the freezer compartment fan may be operated.

Meanwhile, the level of power consumption in the heater operation modePddT in FIG. 9 may be greater than the level of power consumption of theR+F level cooling power.

FIG. 10 is a diagram illustrating temperature change waveforms of anevaporator in response to the defrost heater being operated only in thecontinuous operation mode and in response to the continuous operationmode and the pulse operation mode being mixed.

In particular, in (a) of FIG. 10 , CVa represents a temperature changewaveform in response to the defrost heater being operated only in thecontinuous operation mode, and CVb represents a temperature changewaveform in response to the defrost heater being operated by mixing thecontinuous operation mode and the pulse operation mode.

According to CVa, the defrost heater 330 is continuously turned on, andmay be turned off at a time point Tx, as shown in (b) of FIG. 10 .

According to CVb, the defrost heater 330 operates during the Pohmperiod, as shown in (c) of FIG. 10 .

That is, during the Ponm period including up to a Tpa time point, thecontinuous operation mode is performed, and the pulse operation mode isperformed during a Pofn period from Tpa to Tpb.

Trf1 represents a phase-change temperature, and may be, for example, 0°C. Meanwhile, Trf2 represents a defrost end temperature, for example,may be 5° C.

Meanwhile, a region between Trf1 and Trf2 may indicate a defrostingregion in which defrosting is actually performed, and a region exceedingTrf2 may indicate an overheating region in which excessive defrosting isperformed.

In order to actually effectively perform defrosting, it is preferablethat a size of the overheating region is reduced and a size of thedefrosting region is increased.

Accordingly, in the present disclosure, the continuous operation modeand the pulse operation mode of the defrost heater 300 are mixed inorder to reduce the size of the overheating region and increase the sizeof the defrosting region.

Meanwhile, the controller 310 may be configured to control a peaktemperature arrival point Qd of the evaporator 122 when the continuousoperation mode Pona and the pulse operation mode Ponb are performed inthe defrost operation mode Pdf to be later than a peak temperaturearrival point Qc of the evaporator 122 when the defrost heater 330 isonly continuously turned on in the defrost operation mode Pdf.Accordingly, it is possible to improve the defrosting efficiency andpower consumption when the continuous operation mode Pona and the pulseoperation mode Ponb are performed.

Meanwhile, the controller 310 may be configured to control a size of asecond section Arbb related to a temperature versus time between aphase-change temperature Trf1 and a defrost end temperature Trf2 inresponse to the continuous operation mode and the pulse operation modebeing performed in the defrost operation mode Pdf to be greater than asize of a first section Arab related to a temperature versus timebetween the phase-change temperature Trf1 and the defrost endtemperature Trf2 in response to the defrost heater being onlycontinuously turned on in the defrost operation mode Pdf. Accordingly,it is possible to improve the defrosting efficiency and powerconsumption when the continuous operation mode Pona and the pulseoperation mode Ponb are performed.

Meanwhile, the controller 310 may be configured to control an effectivedefrost when the continuous operation mode Pona and the pulse operationmode Ponb are performed in the defrost operation mode Pdf to be greaterthan an effective defrost when the defrost heater 330 is onlycontinuously turned on in the defrost operation mode Pdf. Accordingly,it is possible to improve the defrosting efficiency and powerconsumption when the continuous operation mode Pona and the pulseoperation mode Ponb are performed.

Meanwhile, the controller 310 may be configured to control a heater OFFtime point Tpb when the continuous operation mode Pona and the pulseoperation mode Ponb are performed in the defrost operation mode Pdf tobe later than a heater OFF time point Tx when the defrost heater 330 isonly continuously turned on in the defrost operation mode Pdf.Accordingly, it is possible to improve the defrosting efficiency andpower consumption when the continuous operation mode Pona and the pulseoperation mode Ponb are performed.

Meanwhile, the controller 310 may be configured to control a periodTpb-Qd between the heater OFF time point Tpb and a peak temperaturearrival time Qd of the evaporator 122 when the continuous operation modePona and the pulse operation mode Ponb are performed in the defrostoperation mode Pdf to be greater than a period Tx-Qc between the heaterOFF time point and the peak temperature arrival time Qc of theevaporator 122 when the defrost heater 330 is only continuously turnedon in the defrost operation mode Pdf. Accordingly, it is possible toimprove the defrosting efficiency and power consumption when thecontinuous operation mode Pona and the pulse operation mode Ponb areperformed.

Meanwhile, the controller 310 may be configured to control a periodTpb-Qh during which a temperature maintains above the phase-changetemperature Trf1 when the continuous operation mode Pona and the pulseoperation mode Ponb are performed in the defrost operation mode Pdf tobe greater than a period Tx-Qg during which a temperature maintainsabove the phase-change temperature Trf1 when the defrost heater 330 isonly continuously turned on in the defrost operation mode Pdf.Accordingly, it is possible to improve the defrosting efficiency andpower consumption when the continuous operation mode Pona and the pulseoperation mode Ponb are performed

Meanwhile, the controller 310 may be configured to control a periodTpb-Qh between the heater OFF time point Tpb to a time point at which atemperature falls below a phase-change temperature Trf1 when thecontinuous operation mode Pona and the pulse operation mode Ponb areperformed in the defrost operation mode Pdf to be less than a periodTx-Qg between the heater OFF time point Tx to a time point Qg at whichthe temperature falls below the phase-change temperature Trf1 when thedefrost heater 330 is only continuously turned on in the defrostoperation mode Pdf. Accordingly, it is possible to improve thedefrosting efficiency and power consumption when the continuousoperation mode Pona and the pulse operation mode Ponb are performed.

Meanwhile, the controller 310 may be configured to control a size of anoverheat temperature region Arba equal to higher than the defrosting endtemperature Trf2 when the continuous operation mode Pona and the pulseoperation mode Ponb are performed in the defrost operation mode Pdf tobe less than an overheat temperature region Araa equal to higher thanthe defrosting end temperature Trf2 when the defrost heater 330 is onlycontinuously turned on in the defrost operation mode Pdf. Accordingly,it is possible to improve the defrosting efficiency and powerconsumption when the continuous operation mode Pona and the pulseoperation mode Ponb are performed.

In FIG. 10 , (d) shows a cooling power supply waveform COa in the caseof only continuously turning on the defrost heater 330 and a coolingpower supply waveform COb in the case of performing a continuousoperation mode Pona and a pulse operation mode Ponb.

Referring to the drawing, the controller 310 may be configured tocontrol a cooling power supply time point Tcb according to a normalcooling operation mode Pga when the continuous operation mode Pona andthe pulse operation mode Ponb are performed in the defrost operationmode Pdf to be later than a cooling power supply time point Tcaaccording to the normal cooling operation mode Pga when the defrostheater 330 is only continuously turned on in the defrost operation modePdf.

Accordingly, it is possible to improve the defrosting efficiency andpower consumption. Accordingly, it is possible to improve the defrostingefficiency and power consumption when the continuous operation mode Ponaand the pulse operation mode Ponb are performed.

FIG. 11 is a diagram illustrating an operating method in a pulseoperation mode according to an embodiment of the present disclosure.

Referring to the drawing, the controller 310 controls the defrost heater330 to be turned on based on the heater operation mode, in particular,based on the continuous operation mode (S1115).

Next, the controller 310 calculates a change rate ΔT of a temperaturedetected by the temperature sensor 320 during the operation of thedefrost heater 330, and determines whether the change rate ΔT of thetemperature is equal to or greater than a first reference value ref1(S1120).

For example, when the change rate ΔT of the temperature during thecontinuous operation of the defrost heater 330 is less than the firstreference value ref1, the controller 310 may control the defrost heater330 to continuously operate.

Meanwhile, when the change rate ΔT of the temperature during thecontinuous operation of the defrost heater 330 is equal to or greaterthan the first reference value ref1, the controller 310 may temporarilyturn off the defrost heater 330 (S1125).

Next, the controller 310 calculates the change rate ΔT of thetemperature detected by the temperature sensor 320 after the defrostheater 330 is temporarily turned off, and determine whether the changerate ΔT of the temperature is less than or equal to a second referencevalue ref2 (S1128).

When the change rate ΔT of the temperature detected by the temperaturesensor 320 is less than or equal to the second reference value ref2after the defrost heater 330 is temporarily turned off, the controller310 is configured to turn on the defrost heater. That is, the controller310 controls to perform step S1115.

As such, when steps 1115 to 1128 are repeated, the pulse operation modeof the defrost heater 330 is performed.

Meanwhile, in step S1128, after the defrost heater 330 is temporarilyturned off, when the change rate ΔT of the temperature exceeds thesecond reference value ref2, the controller 310 determines a pulseoperation mode end condition is met. When the pulse operation mode endcondition is met (S1130), the controller 310 ends the pulse operationmode and controls the heater to be turned off (S1140).

The pulse operation mode end condition may correspond to the pulseoperation mode time point.

For example, the pulse operation mode end time point may be a time atwhich the temperature detected by the temperature sensor 320 falls belowthe phase-change temperature Trf1.

As another example, the pulse operation mode end time point may be anend time point of the defrosting operation or an end time point of theheater operation mode.

Meanwhile, when the defrosting operation start time point To arrives,the controller 310 controls to perform the defrost operation mode Pdfand controls to perform the continuous operation mode Pona in which thedefrost heater 330 is continuously turned on and the pulse operationmode Ponb in which the defrost heater 330 is repeatedly turned on andoff based on the defrost operation mode Pdf, and in response toperforming the pulse operation mode Ponb, the controller controls thedefrost heater 330 to be turned on and off based on the change rate ΔTof the temperature detected by the temperature sensor 320. Accordingly,since defrosting may be performed based on the change rate ΔT of thetemperature, it is possible to improve defrost efficiency and powerconsumption.

In particular, since defrosting is performed according to the actualamount of frost ICE of the evaporator 122, it is possible to improvedefrost efficiency and power consumption.

Meanwhile, the controller 310 may be configured to perform thecontinuous operation mode Pona or the pulse operation mode Ponb based onthe change rate ΔT of the temperature detected by the temperature sensor320. Accordingly, it is possible to improve the defrosting efficiencyand power consumption.

Meanwhile, the controller 310 may be configured to operate the heaterwith power inversely proportional to the change rate ΔT of thetemperature detected by the sensor during the pulse operation mode Ponb.Accordingly, it is possible to improve the defrosting efficiency andpower consumption.

Meanwhile, the controller 310 may be configured to decrease a period ofperforming the defrost operation mode Pdf as the number of opening timesthe cooling compartment door increases. Accordingly, it is possible toimprove the defrosting efficiency and power consumption.

FIG. 12A is a diagram showing a temperature waveform of the evaporatorwhen there is a large amount of frost formation.

In FIG. 12A, (a), CVma represents a temperature change waveform inresponse to the defrost heater being operated only in the continuousoperation mode, and CVmb represents a temperature change waveform inresponse to the defrost heater being operated by mixing the continuousoperation mode and the pulse operation mode.

According to CVma, the defrost heater 330 may be continuously turned on,and may be turned off at a time point Tmg, as shown in (b) of FIG. 12A.

According to CVmb, as shown in (c) of FIG. 12A, the defrost heater 330is continuously turned on during a Tma period and turned off during Tmaand Tmb, during Tmc and Tmd, during Tme and Tmf, and during Tmg and Tmh,and the defrost heater 330 is turned on during Tmb and Tmc, during Tmdand Tme, during Tmf and Tmg, and during Tmh and Tmi.

That is, from Tma to Tmi, the defrost heater 330 operates in the pulseoperation mode.

Meanwhile, the controller 310 controls the defrost heater 330 to becontinuously turned on based on the continuous operation mode Pona, andin the ON state of the defrost heater 330, when the change rate ΔT ofthe ambient temperature of the evaporator 122 detected by thetemperature sensor 320 is equal to or greater than the first referencevalue ref1, the controller 310 may enter the pulse operation mode Ponband control the defroster heater 330 to be turned off. Accordingly, itis possible to improve the defrosting efficiency and power consumption.

Meanwhile, when the defrost heater 330 is turned off during the pulseoperation mode Ponb and the change rate ΔT of the temperature around theevaporator 122 is equal to or less than the second reference value ref2less than the first reference value ref1, the controller 310 may controlthe defrost heater 330 to be turned on. Accordingly, it is possible toimprove the defrosting efficiency and power consumption.

Meanwhile, when the defrost heater 330 is turned on during the pulseoperation mode Ponb and the change rate ΔT of the temperature around theevaporator 122 is equal to or greater than the first reference valueref1, the controller 310 may control the defrost heater 330 may to beturned on. Accordingly, it is possible to improve the defrostingefficiency and power consumption.

Meanwhile, the controller 310 may control the defrost heater 330 to becontinuously turned on based on the continuous operation mode Pona, andbased on the pulse operation mode Ponb, the controller 310 mayrepeatedly turned on and off the defrost heater 320 so that the changerate ΔT of the temperature around the evaporator 122 may be between thefirst reference value ref1 and the second reference value ref2.Accordingly, it is possible to improve the defrosting efficiency andpower consumption.

FIG. 12B is a diagram showing a temperature waveform of the evaporatorwhen the amount of frost formation is less than that of FIG. 12A.

In (a) of FIG. 12B, CVna represents a temperature change waveform inresponse to the defrost heater being operated only in the continuousoperation mode, and CVnb represents a temperature change waveform inresponse to the defrost heater being operated by mixing the continuousoperation mode and the pulse operation mode.

According to CVna, the defrost heater 330 may be continuously turned onand may be turned off at a time point Tng, as shown in (b) of FIG. 12B.

According to CVnb, as shown in (c) of FIG. 12 b , the defrost heater 330is continuously turned on during a period of Tna, and the defrost heater330 is turned off during Tna and Tnb, during Tnc and Tnd, during Tne andTnf, and during Tng and Tnh, and turned on during Tnb and Tnc, duringTnd and Tne, during Tnf and Tng, and during Tnh and Tni.

That is, from Tna to Tni, the defrost heater 330 operates in the pulseoperation mode.

FIG. 13 is a view showing a region requiring cooling power supply and aregion requiring defrosting according to temperatures of therefrigerating compartment and the freezer compartment.

Referring to the drawing, the horizontal axis may indicate a temperatureof the refrigerating compartment, and the vertical axis may indicate atemperature of the freezer compartment.

When a temperature is equal to or lower than a reference temperature ofthe freezer compartment refma, it may indicate that a freezing capacityis sufficient, and when the temperature is equal to or lower than areference temperature of the refrigerating compartment refmb, it mayindicate that cooling capacity of the refrigerating compartment issufficient.

An Arma region in the drawing is a region in which freezing capacity ofthe freezer compartment and cooling capacity of the refrigeratingcompartment are sufficient, and may be a region requiring defrosting.

Accordingly, when the defrosting required region is satisfied based onthe temperature of the refrigerating compartment and the freezercompartment, the controller 310 may be configured to perform thecontinuous operation mode and the pulse operation mode described above.In particular, ON/OFF of the defrost heater 330 in the pulse operationmode may be controlled based on a temperature change rate around theevaporator 122.

Meanwhile, the Armb region in the drawing may be a region in which bothcooling power of the freezer compartment and cooling power of therefrigerating compartment are insufficient, and may be a cooling powersupply requiring region requiring cooling power supply.

Accordingly, the controller 310 may control supply of cooling power. Forexample, a compressor may be operated or a thermoelectric element may beoperated to control supply of cooling power.

FIG. 14 is a flowchart illustrating a method of operating a defrostheater according to another embodiment of the present disclosure, andFIGS. 15A to 15D are diagrams referenced in the description of FIG. 14 .

First, referring to FIG. 14 , the controller 310 of the refrigerator 100according to an embodiment of the present disclosure determines whethera defrosting operation start time point arrives for defrosting (S610).

For example, the controller 310 of the refrigerator 100 may determinewhether a defrosting operation start time point arrives, whileperforming the normal cooling operation mode Pga. The defrostingoperation start time point may vary according to a defrost cycle.

Meanwhile, when a defrosting operation start condition is satisfied, forexample, in response to a defrosting operation start time pointarriving, the controller 310 of the refrigerator 100 may end the normalcooling operation mode and control to perform the defrost operation modePdf.

Meanwhile, the defrost operation mode Pdf may include a pre-defrostcooling mode Pbd, a heater operation mode PddT, and a post-defrostcooling mode pbf.

Meanwhile, the heater operation mode PddT may include a continuousoperation mode Pona in which the defrost heater 330 is continuouslyturned on, and a pulse operation mode Ponb in which the defrost heater330 is repeatedly turned on and off.

Meanwhile, the controller 310 of the refrigerator 100 may control thedefrost heater 330 to be continuously turned on based on the heateroperation mode PddT in the defrost operation mode Pdf (S615).

In particular, the controller 310 may control the defrost heater 330 tobe continuously turned on based on the continuous operation mode Pona inthe heater operation mode PddT.

Next, the controller 310 of the refrigerator 100 may control the pulseoperation mode Ponb, in which the defrost heater 330 is repeatedlyturned on and off, to be performed by a heater pulse after the defrostheater 330 is continuously turned on (S620).

Meanwhile, while performing the pulse operation mode Ponb, thecontroller 310 may determine whether the return condition to thecontinuous operation mode is satisfied (S623), and if so, control thecontinuous operation mode to be performed again.

For example, when the switching element RL of FIG. 7A is continuouslyturned on and off, the possibility of loss of the switching element RLmay increase. Accordingly, the controller 310 may control the pulseoperation mode to end, and the continuous operation mode to be performedagain.

Accordingly, even in the pulse operation mode Ponb, when the defrostingof the frost is not smoothly performed, the defrosting may be stablyperformed.

Next, the controller 310 of the refrigerator 100 determines whether itis the pulse operation mode end time point (S630), and if so, turns offthe defrost heater 330 (S640).

For example, the pulse operation mode end point time may be a time pointat which the temperature detected by the temperature sensor 320 fallsbelow the phase change temperature Trf1.

As another example, the pulse operation mode end time point may be adefrost operation end time point or a heater operation mode end timepoint.

Meanwhile, without determining the return condition to the continuousoperation mode in step 623, after performing the pulse operation modePonb, it is also possible to re-perform the continuous operation modePonc.

For example, the controller 310 may control the continuous operationmode Ponc to be performed again after performing the pulse operationmode Ponb for stable defrosting. Accordingly, it is possible to improvethe defrosting efficiency and reduce the power consumption. Inparticular, since the defrosting is performed according to the amount offrost of the actual evaporator, it is possible to improve defrostingefficiency and power consumption.

Meanwhile, while performing the pulse operation mode Ponb in step 623, amethod of determining whether the return condition to the continuousoperation mode is satisfied, various examples are possible.

For example, when the value related to the temperature detected by thetemperature sensor 320 does not reach the reference value whileperforming the pulse operation mode Ponb, the controller 310 maydetermine that the defrosting is not smooth, and control the continuousoperation mode Ponc to be performed for quick defrosting. Accordingly,it is possible to improve the defrosting efficiency while stablyperforming the defrosting.

Meanwhile, when the temperature detected by the temperature sensor 320is below the reference temperature while performing the pulse operationmode Ponb, the controller 310 may control the continuous operation modePonc to be performed for quick defrosting. Accordingly, it is possibleto improve the defrosting efficiency while stably performing thedefrosting.

Meanwhile, when the change rate □T of the temperature detected by thetemperature sensor 320 is below the reference temperature □T whileperforming the pulse operation mode Ponb, the controller 310 maydetermine that the defrosting is not smooth, and control the continuousoperation mode Ponc to be performed for quick defrosting. Accordingly,it is possible to improve the defrosting efficiency while stablyperforming the defrosting.

Meanwhile, when the temperature detected by the temperature sensor 320does not reach the target temperature within a certain time whileperforming the pulse operation mode Ponb, the controller 310 maydetermine that the defrosting is not smooth, and control the continuousoperation mode Ponc to be performed for quick defrosting. Accordingly,it is possible to improve the defrosting efficiency while stablyperforming the defrosting.

Meanwhile, when a sum Ma+Mb+ . . . Mn of the ON time of the defrostheater 330 is above the reference level while performing the pulseoperation mode Ponb, the controller 310 may determine that thedefrosting is not smooth, and control the continuous operation mode Poncto be performed for quick defrosting. Accordingly, it is possible toimprove the defrosting efficiency while stably performing thedefrosting.

Meanwhile, when a sum of the number of opening times of turn on of thedefrost heater 330 is above the reference level while performing thepulse operation mode Ponb, the controller 310 may determine that thedefrosting is not smooth, and control the continuous operation mode Poncto be performed for quick defrosting. Accordingly, it is possible toimprove the defrosting efficiency while stably performing thedefrosting.

Meanwhile, when the sum Ma+Mb+ . . . , Mn of the ON time of the defrostheater 330 is greater than the sum Mo of the continuous ON time of thedefrost heater 330 of the continuous operation mode while performing thepulse operation mode Ponb, the controller 310 may determine that thedefrosting is not smooth, and control the continuous operation mode Poncto be performed for quick defrosting. Accordingly, it is possible toimprove the defrosting efficiency while stably performing thedefrosting.

Meanwhile, when the open period is greater than or equal to theallowable period while performing the pulse operation mode Ponb, thecontroller 310 may determine that the defrosting is not smooth, andcontrol the continuous operation mode Ponc to be performed for quickdefrosting. Accordingly, it is possible to improve the defrostingefficiency while stably performing the defrosting.

Meanwhile, when the humidity in the refrigerator is greater than orequal to the reference humidity while performing the pulse operationmode Ponb, the controller 310 may determine that the defrosting is notsmooth, and control the continuous operation mode Ponc to be performedfor quick defrosting. Accordingly, it is possible to improve thedefrosting efficiency while stably performing the defrosting.

FIG. 15A is a diagram illustrating an example of a pulse waveformindicating an operation of a defrost heater according to an embodimentof the present disclosure.

Referring to the drawing, a horizontal axis of a pulse waveform Pshm mayindicate time, and a vertical axis may indicate a level.

When a defrosting operation start time point To arrives while performingthe normal cooling operation mode Pga, the controller 310 of therefrigerator 100 may control the normal cooling operation mode Pga toend and the defrost operation mode Pdf to be performed.

The defrost operation mode Pdf may include the pre-defrost cooling modePbd between Toa and Ta, the heater operation mode PddT between Ta andTd, and the post-defrost cooling mode pbf between Td and Te.

Meanwhile, after the defrost operation mode Pdf ends, the normal coolingoperation mode Pgb is performed again.

The defrost heater 330 is turned off in the normal cooling operationmode Pga and the normal cooling operation mode Pgb.

Meanwhile, the defrost heater 330 may be turned off in the pre-defrostcooling mode Pbd and the post-defrost cooling mode pbf of the defrostoperation mode Pdf.

Meanwhile, the defrost heater 330 may be continuously turned on in thecontinuous operation mode Pona in the heater operation mode PddT, mayrepeat the turn on and off in the pulse operation mode Ponb in theheater operation mode PddT, and may be continuously turned on in thecontinuous operation mode Ponc in the heater operation mode PddT.

Unlike FIG. 8A, according to FIG. 15A, after the pulse operation modePonb, there is a difference in that the continuous operation mode Poncis further performed.

As described in the description of FIG. 14 , when the return conditionto the continuous operation mode Ponc of the defrost heater 330 arriveswhile performing the pulse operation mode Ponb, the controller 310 maycontrol the continuous operation mode Ponc to be further performed.

The continuous operation mode Pona may be performed between Ta and Tb,and the pulse operation mode Ponb may be performed between Tb and Tc.

An additional continuous operation mode Ponc may be performed betweenTcm and Td. In the drawing, it is exemplified that the period duringwhich the additional continuous operation mode Ponc is performed is Mz.

By this additional continuous operation mode Ponc, it is possible toimprove the defrosting efficiency while stably performing thedefrosting.

FIG. 15B is a diagram illustrating another example of a pulse waveformindicating an operation of a defrost heater according to an embodimentof the present disclosure.

A pulse waveform Pshn of FIG. 15B is similar to the pulse waveform Pshmof FIG. 15A, but the additional continuous operation mode Ponc isdifferent in that it is performed between Tcm and Tcn.

In the drawing, it is exemplified that My, which is the duration of theadditional continuous operation mode Ponc, is less than Mz of FIG. 15A.

The controller 310 may vary the period during which the continuousoperation mode Ponc is performed based on the difference between thevalue related to the temperature detected by the temperature sensor 320and the reference value. For example, as the difference decreases, it ispossible to control the period during which the continuous operationmode Ponc is performed to decrease. By this additional continuousoperation mode Ponc, it is possible to improve the defrosting efficiencywhile stably performing the defrosting.

Meanwhile, the controller 310 may vary the period during which thecontinuous operation mode Ponc is performed based on the differencebetween the temperature detected by the temperature sensor 320 and thereference temperature while performing the pulse operation mode Ponb.For example, as the difference decreases, it is possible to control theperiod during which the continuous operation mode Ponc is performed todecrease.

Meanwhile, the controller 310 may vary the period during which thecontinuous operation mode Ponc is performed based on the differencebetween the change rate □T of the temperature detected by thetemperature sensor 320 and the change rate □T of the referencetemperature while performing the pulse operation mode Ponb. For example,as the difference decreases, it is possible to control the period duringwhich the continuous operation mode Ponc is performed to decrease.

Meanwhile, the controller 310 may vary the period during which thecontinuous operation mode Ponc is performed based on the differencebetween the temperature detected by the temperature sensor 320 and thetarget temperature while performing the pulse operation mode Ponb. Forexample, as the difference decreases, it is possible to control theperiod during which the continuous operation mode Ponc is performed todecrease.

Meanwhile, the controller 310 may vary the period during which thecontinuous operation mode Ponc is performed based on the differencebetween the reference level and the sum Ma+Mb+ . . . Mn of the on timeof the defrost heater 330 while performing the pulse operation modePonb. For example, as the difference decreases, it is possible tocontrol the period during which the continuous operation mode Ponc isperformed to decrease.

Meanwhile, the controller 310 may vary the period during which thecontinuous operation mode Ponc is performed based on the differencebetween the reference number of opening times and the sum of the numberof opening times of turn on of the defrost heater 330 while performingthe pulse operation mode Ponb. For example, as the difference decreases,it is possible to control the period during which the continuousoperation mode Ponc is performed to decrease.

Meanwhile, the controller 310 may vary the period during which thecontinuous operation mode Ponc is performed based on the differencebetween the sum Mo of the continuous ON time and the sum Ma+Mb+ . . . Mnof the ON time of the defrost heater 330 while performing the pulseoperation mode Ponb. For example, as the difference decreases, it ispossible to control the period during which the continuous operationmode Ponc is performed to decrease.

Meanwhile, the controller 310 may vary the period during which thecontinuous operation mode Ponc is performed based on the differencebetween the humidity in the refrigerator and the reference humiditywhile performing the pulse operation mode Ponb. For example, as thedifference decreases, it is possible to control the period during whichthe continuous operation mode Ponc is performed to decrease.

FIG. 15C is a diagram illustrating another example of a pulse waveformindicating an operation of a defrost heater according to an embodimentof the present disclosure.

A pulse waveform Psho of FIG. 15 c is similar to the pulse waveform(Pshm) of FIG. 15A, but there is a difference in that after the pulseoperation mode Ponb, an additional continuous operation mode Ponab andan additional pulse operation mode ponbb are further performed.

In the drawing, it is exemplified that after Tc, an additionalcontinuous operation mode Ponab is performed between Ta′ and Tb′, and anadditional pulse operation mode ponbb is performed between Tb′ and Tc′.

Meanwhile, the duration of the additional continuous operation modePonab is preferably less than the duration of the continuous operationmode Pona.

Meanwhile, the duration of the additional pulse operation mode ponbb ispreferably less than the duration of the continuous operation mode Ponb.Accordingly, it is possible to improve the defrosting efficiency whilestably performing the defrosting.

FIG. 16 is a flowchart illustrating a defrosting method according toanother embodiment of the present disclosure, and FIGS. 17A to 17D arediagrams referenced in the description of FIG. 16 .

First, referring to FIG. 16 , the controller 310 of the refrigerator 100according to an embodiment of the present disclosure determines whethera defrosting operation start time point arrives for defrosting (S610).

For example, the controller 310 of the refrigerator 100 may determinewhether it is the defrosting operation start time point, whileperforming the normal cooling operation mode Pga. The defrostingoperation start time point may vary according to a defrost cycle.

Meanwhile, when a defrosting operation start condition is satisfied, forexample, in response to a defrosting operation start time pointarriving, the controller 310 of the refrigerator 100 may end the normalcooling operation mode and control the defrost operation mode Pdf to beperformed.

Meanwhile, the defrost operation mode Pdf may include a pre-defrostcooling mode Pbd, a heater operation mode PddT, and a post-defrostcooling mode pbf.

Meanwhile, the heater operation mode (PddT) may include a continuousoperation mode Pona in which the defrost heater 330 is continuouslyturned on, and a pulse operation mode Ponb in which the defrost heater330 is repeatedly turned on and off.

Meanwhile, the controller 310 of the refrigerator 100 may control thedefrost heater 330 to be continuously turned on based on the continuousoperation mode Pona in the heater operation mode PddT of the defrostoperation mode Pdf (S615).

Next, the controller 310 of the refrigerator 100 determines whether thetemperature detected by the temperature sensor 320 reaches a firsttemperature Tm1 within a first period Pm1 while performing thecontinuous operation mode Pona (S1616).

If so, the controller 310 of the refrigerator 100 may control the pulseoperation mode, in which the defrost heater 330 is repeatedly turned onand off, to be performed by the heater pulse after the defrost heater330 is continuously turned on (S1620).

(a) of FIG. 17A illustrates an example of a temperature waveform Tcvaaround the evaporator 122, and (b) of FIG. 17A illustrates an example ofan operating waveform Psh of the defrost heater 330.

Referring to the drawing, based on the heater operation mode Pon, thecontinuous operation mode (Pona) is performed during the Pm1 periodbetween Ta and Tb.

Meanwhile, when the temperature detected by the temperature sensor 320reaches the first temperature Tm1 within the first period Pm1, or asillustrated in the drawing, at Tb, which is the end time of the firstperiod Pm1, while performing the continuous operation mode Pona, thecontroller 310 of the refrigerator 100 may control the pulse operationmode Ponb to be performed after Tb.

That is, after the time Tb, the controller 310 of the refrigerator 100may control the defrost heater 330 to be turned off during the periodpf1 and then the defrost heater 330 to be repeatedly turned on and off.

As such, when the amount of frost formed on the evaporator 122 is small,after the continuous operation mode Pona is performed, by controllingthe pulse operation mode Ponb to be performed, it is possible to improvethe defrosting efficiency and reduce the power consumption.

Next, the controller 310 of the refrigerator 100 determines whether itis the pulse operation mode end time point (S1630), and if so, turns offthe defrost heater 330 (S1640).

For example, the pulse operation mode end point time may be a time pointat which the temperature detected by the temperature sensor 320 fallsbelow the phase change temperature Trf1.

As another example, the pulse operation mode end time point may be adefrost operation end time point or a heater operation mode end timepoint.

Meanwhile, in step S1616, when the temperature detected by thetemperature sensor 320 does not reach the first temperature Tm1 withinthe first period Pm1 while performing the continuous operation modePona, step S1617 may be performed.

That is, when the temperature detected by the temperature sensor 320does not reach a first temperature Tm1 within the first period Pm1 whileperforming the continuous operation mode Pona, the controller 310 of therefrigerator 100 determines whether the first temperature Tm1 arrivalperiod is greater than or equal to the second period (S1617).

If so, it is determined that the amount of frost formed on theevaporator 122 is large, and the continuous operation mode Pona may becontrolled to be continuously performed (S1623).

(b) of FIG. 17A illustrates another example of a temperature waveformTcvb around the evaporator 122, and (b) of FIG. 17B illustrates anotherexample of an operating waveform Pshb1 of the defrost heater 330.

Referring to the drawing, based on the heater operation mode Pon, thecontinuous operation mode Pona is performed during the period Pm1between Ta and Tb.

Meanwhile, when the temperature detected by the temperature sensor 320does not reach a first temperature Tm1 within the first period Pm1 whileperforming the continuous operation mode Pona1, the controller 310 ofthe refrigerator 100 determines whether the first temperature Tm1arrival period is greater than or equal to the second period pm2.

In the drawing, it is exemplified that the temperature detected by thetemperature sensor 320 reaches the end time of the second period pm2.

Accordingly, the controller 310 of the refrigerator 100 may control thecontinuous operation mode Pona1 to be performed during the periods Taand Tc.

In addition, the controller 310 of the refrigerator 100 may controlthat, during the heater operation mode Pon, only the continuousoperation mode Pona1 is performed and the pulse operation mode (Ponb) isnot performed. Accordingly, when the amount of frost formed on theevaporator 122 is large, it is possible to control to efficientlyperform defrosting.

Meanwhile, unlike the drawing, the controller 310 of the refrigerator100 may control the continuous operation mode Pona1 to be performedduring a predetermined period after the period Tc.

Meanwhile, after the continuous operation mode Pona1 of FIG. 17B, stepS1622 may be performed again.

Meanwhile, in step 1617, when the first temperature Tm1 arrival periodof the temperature detected by the temperature sensor 320 is not greaterthan or equal to the second period but is between the first period andthe second period while performing the continuous operation mode Pona,step S1618 may be performed

That is, the controller 310 of the refrigerator 100 determines whetherthe temperature detected by the temperature sensor 320 reaches thesecond temperature Tm2 between the first period and the second periodwhile performing the continuous operation mode Pona (S1618). If so, thedefrost heater is turned off (S1619), and the defrost heater may becontrolled to be turned on and off based on the pulse operation mode(S1621).

(a) of FIG. 17C illustrates another example of a temperature waveformTcvc around the evaporator 122, and (b) of FIG. 17C illustrates anotherexample of an operating waveform Pshb2 of the defrost heater 330.

Referring to the drawing, based on the heater operation mode Pon2, thecontinuous operation mode is performed during the period Pm1 between Taand Tb.

Meanwhile, when the temperature detected by the temperature sensor 320does not reach the first temperature Tm1 within the first period Pm1while performing the continuous operation mode, the controller 310 ofthe refrigerator 100 determines whether the first temperature Tm1arrival period is greater than or equal to the second period pm2 orbetween the first period pm1 and the second period pm2.

In the drawing, it is exemplified that the temperature detected by thetemperature sensor 320 reaches the first temperature Tm1 in Tk betweenthe first period pm1 and the second period pm2, and the temperaturedetected by the temperature sensor 320 reaches the second temperatureTm2 in Tm between the first period pm1 and the second period pm2.

Accordingly, the controller 310 of the refrigerator 100 may beconfigured to perform the continuous operation mode until the time pointTm at which a temperature reaches the second temperature Tm2

In addition, after the first OFF of the defrost heater 330 after thetime point Tm, the pulse operation mode Ponb2 may be controlled to beperformed.

Meanwhile, as the continuous operation mode continues, in considerationof the heat of the switching element RL of FIG. 7A, tit is preferablethat the first OFF period psf2 of the defrost heater 330 after the timepoint Tm is greater than the OFF period during the On and off of thepulse operation mode Ponb2.

Meanwhile, it is preferable that the first OFF period psf2 of thedefrost heater 330 after the time point Tm when the pulse operation modePonb2 is performed is greater than the first OFF period pof1 of thedefrost heater 330 after the time point Tb when the pulse operation modePonb of FIG. 17A is performed. Accordingly, it is possible to protectthe switching element RL of FIG. 7A and the like.

Meanwhile, according to FIGS. 17A to 17C, the controller 310 may beconfigured to, as the change rate of the temperature detected by thetemperature sensor 320 decreases while performing the continuousoperation mode Pon, increase a delay of the start time point of thepulse operation mode Ponb.

That is, compared to FIG. 17A, in the case of FIG. 17C, the change rateof the temperature detected by the temperature sensor 320 is smaller,and accordingly, the start time point of the pulse operation mode isfurther delayed.

Meanwhile, compared to FIG. 17C, in the case of FIG. 17B, the changerate of the temperature detected by the temperature sensor 320 issmaller, and accordingly, the pulse operation mode may not start at all.

Meanwhile, the controller 310 may be configured to, as the change rateof the temperature detected by the temperature sensor decreases whileperforming the continuous operation mode Pona, increase the duration ofthe pulse operation mode Pona.

For example, compared to FIG. 17A, in the case of FIG. 17C, the changerate of the temperature detected by the temperature sensor 320 issmaller, and accordingly, the duration of the continuous operation modeis a period between Ta and Tm, and is greater than the period between Taand Tb of FIG. 17A.

Meanwhile, compared to FIG. 17C, in the case of FIG. 17B, the changerate of the temperature detected by the temperature sensor 320 issmaller, and accordingly, the duration of the continuous operation modeis a period between Ta and Tc, and is greater than the period between Taand Tm of FIG. 17B. Accordingly, it is possible to efficiently performthe defrosting.

Meanwhile, unlike FIGS. 17A to 17C, when the temperature detected by thetemperature sensor 320 reaches the first temperature Tm1 between thefirst period Pm1 and the period Pm2 while performing the continuousoperation mode, the controller 310 may control the pulse operation modePonb to be performed after the defrost heater 310 is turned off withoutdetermining whether the second period Pm2 arrives.

The controller 310 may be configured to control the OFF period of thedefrost heater 310 before the pulse operation mode Ponb is performedwhen the temperature detected by the temperature sensor 320 reaches thefirst temperature Tm1 between the first period Pm1 and the second periodPm2 to be greater than the OFF period of the defrost heater 310 beforethe pulse operation mode Ponb is performed when the temperature detectedby the temperature sensor 320 reaches the first temperature Tm1 withinthe first period Pm1. Accordingly, it is possible to efficiently performthe defrosting.

In the refrigerator according to the present disclosure, theconfiguration and the method of the embodiments as described above arenot restrictively applied. Rather, all or some of the embodiments may beselectively combined with each other so that the embodiments may bevariously modified.

In addition, although the preferred embodiments of the presentdisclosure have been illustrated, the present disclosure is not limitedto the specific embodiments described above, and can be variouslymodified by those skilled in the art to which the present disclosurepertains without departing from the gist of the present disclosureclaimed in the claims, and these modifications should not be understoodindividually from the technical ideas or prospects of the presentdisclosure.

INDUSTRIAL APPLICABILITY

The present disclosure can be applied to a refrigerator, and moreparticularly, can be applied to a refrigerator capable of improvingdefrosting efficiency and power consumption.

What is claimed is:
 1. A refrigerator, comprising: an evaporator configured to perform heat exchange; a defrost heater configured to operate to remove frost formed on the evaporator; a temperature sensor configured to detect an ambient temperature of the evaporator; and a controller configured to control the defrost heater, wherein, in response to a defrosting operation start time point arriving, the controller is configured to perform a defrost operation mode, perform a continuous operation mode, in which the defrost heater is continuously turned on, and a pulse operation mode, in which the defrost heater is repeatedly turned on and off based on the defrost operation mode, and perform the continuous operation mode again after performing the pulse operation mode.
 2. The refrigerator of claim 1, wherein, in response to a return condition to the continuous operation mode of the defrost heater arriving while performing the pulse operation mode, the controller is configured to perform the continuous operation mode.
 3. The refrigerator of claim 1, wherein, in response to a value related to the temperature detected by the temperature sensor doing not reach a reference value while performing the pulse operation mode, in response to the temperature detected by the temperature sensor being below a reference temperature while performing the pulse operation mode, in response to a change rate of the temperature detected by the temperature sensor being less than or equal to a change rate of the reference temperature while performing the pulse operation mode, or in response to the temperature detected by the temperature sensor doing not reach a target temperature within a certain time while performing the pulse operation mode, the controller is configured to perform the continuous operation mode.
 4. The refrigerator of claim 1, wherein, in response to a sum of an ON time of the defrost heater while performing the pulse operation mode being greater than or equal to a reference level, in response to a sum of the number of opening times the defrost heater while performing the pulse operation mode being greater than or equal to the reference number of opening times, or in response to the sum of the ON time of the defrost heater while performing the pulse operation mode being greater than a sum of a continuous ON time of the defrost heater in the continuous operation mode, the controller is configured to perform the continuous operation mode.
 5. The refrigerator of claim 1, wherein, in response to a door open period being greater than or equal to an allowable period while performing the pulse operation mode, the controller is configured to perform the continuous operation mode.
 6. The refrigerator of claim 1, wherein, in response to humidity in the refrigerator being greater than or equal to reference humidity while performing the pulse operation mode, the controller is configured to perform the continuous operation mode.
 7. The refrigerator of claim 1, wherein, in response to a defrosting operation start time point arriving while performing a normal cooling operation mode, the controller is configured to perform the defrost operation mode including a pre-defrost cooling mode, a heater operation mode, and a post-defrost cooling mode, and perform the continuous operation mode of the defrost heater, and the pulse operation mode, in which the defrost heater is repeatedly turned on and off, based on the heater operation mode.
 8. The refrigerator of claim 1, wherein the controller is configured to continuously turn on the defrost heater based on the continuous operation mode, in response to a change rate of the ambient temperature of the evaporator detected by the temperature sensor being greater than or equal to a first reference value in an ON state of the defrost heater, enter the pulse operation mode and turn off the defrost heater, and in response to the change rate of the ambient temperature of the evaporator being less than or equal to a second reference value less than the first reference value in a state in which the defrost heater is turned off during the pulse operation mode, turn on the defrost heater.
 9. The refrigerator of claim 1, wherein the controller is configured to continuously turn on the defrost heater based on the continuous operation mode, and repeatedly turn on and off the defrost heater for the change rate of the ambient temperature of the evaporator to be between the first reference value and the second reference value based on the pulse operation mode.
 10. The refrigerator of claim 1, wherein as the number of opening times of the cooling compartment door increases, the controller is configured to decrease a duration of the defrost operation mode.
 11. The refrigerator of claim 1, wherein the controller is configured to control a peak temperature arrival time point of the evaporator in response to the continuous operation mode and the pulse operation mode being performed to be later than the peak temperature arrival time point of the evaporator in response to the defrost heater being only continuously turned on in the defrost operation mode.
 12. The refrigerator of claim 1, wherein the controller is configured to control a size of a second section related to temperature versus time between a phase-change temperature and the defrost end temperature in response to the continuous operation mode and the pulse operation mode being performed in the defrost operation mode to be greater than a size of a first section related to temperature versus time between the phase-change temperature and the defrost end temperatures only in response to the defrost heater being continuously turned on in the defrost operation mode.
 13. The refrigerator of claim 1, wherein the controller is configured to control an effective defrost in response to the continuous operation mode and the pulse operation mode being performed in the defrost operation mode to be greater than the effective defrost in response to the defrost heater being only continuously turned on in the defrost operation mode.
 14. The refrigerator of claim 1, wherein the controller is configured to control a heater OFF time point in response to the continuous operation mode and the pulse operation mode being performed in the defrost operation mode to be later than the heater OFF time point in response to the defrost heater being only continuously turned on in the defrost operation mode.
 15. The refrigerator of claim 1, wherein, in response to a defrosting operation start time point arriving, the controller is configured to perform the defrost operation mode including a pre-defrost cooling mode, a heater operation mode, and a post-defrost cooling mode, in response to the temperature detected by the temperature sensor reaching the first temperature within a first period during the continuous operation mode in which the defrost heater is continuously turned on based on the heater operation mode, perform the pulse operation mode in which the defrost heater is repeatedly turned on and off, and in response to the period during which the temperature detected by the temperature sensor reaching the first temperature while performing the continuous operation mode is greater than or equal to a second period greater than the first period, continuously perform the continuous operation mode.
 16. A refrigerator, comprising: an evaporator configured to perform heat exchange; a defrost heater configured to operate to remove frost formed on the evaporator; a temperature sensor configured to detect an ambient temperature of the evaporator; and a controller configured to control the defrost heater, wherein, in response to a defrosting operation start time point arriving, the controller is configured to perform a defrost operation mode, perform a continuous operation mode, in which the defrost heater is continuously turned on, and a pulse operation mode, in which the defrost heater is repeatedly turned on and off based on the defrost operation mode, and in response to a return condition to the continuous operation mode of the defrost heater arriving while performing the pulse operation mode, perform the continuous operation mode again.
 17. A refrigerator, comprising: an evaporator configured to perform heat exchange; a defrost heater configured to operate to remove frost formed on the evaporator; a temperature sensor configured to detect an ambient temperature of the evaporator; and a controller configured to control the defrost heater, wherein, in response to a defrosting operation start time point arriving, the controller is configured to perform the defrost operation mode including a pre-defrost cooling mode, a heater operation mode, and a post-defrost cooling mode, in response to the temperature detected by the temperature sensor reaching the first temperature within a first period during the continuous operation mode in which the defrost heater is continuously turned on based on the heater operation mode, perform the pulse operation mode in which the defrost heater is repeatedly turned on and off, and in response to the period during which the temperature detected by the temperature sensor reaching the first temperature while performing the continuous operation mode is greater than or equal to a second period greater than the first period, continuously perform the continuous operation mode.
 18. The refrigerator of claim 17, wherein, in response to the temperature detected by the temperature sensor reaching a second temperature higher than the first temperature after arriving at the first temperature between the first period and the second period while performing the continuous operation mode, the controller is configured to perform the pulse operation mode after the defrost heater is turned off.
 19. The refrigerator of claim 18, wherein the controller is configured to control an OFF period of the defrost heater before performing the pulse operation mode in response to the temperature detected by the temperature sensor reaching a second temperature higher than the first temperature between the first period and the second period to be greater than the OFF period of the defrost heater before performing the pulse operation mode in response to the temperature detected by the temperature sensor reaching the first temperature within the first period.
 20. The refrigerator of claim 17, wherein, in response to the temperature detected by the temperature sensor reaching the first temperature between the first period and the second period while performing the continuous operation mode, the controller is configured to perform the pulse operation mode after the defrost heater is turned off. 